/*
 * Copyright (c) 2010-2025 Haifeng Li. All rights reserved.
 *
 * Smile is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Smile is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Smile. If not, see <https://www.gnu.org/licenses/>.
 */
package smile.vq;

import java.io.Serializable;

/**
 * Vector quantizer with competitive learning.
 *
 * @author Haifeng Li
 */
public interface VectorQuantizer extends Serializable {
    /**
     *  The label for outliers or noises.
     */
    int OUTLIER = Integer.MAX_VALUE;

    /**
     * Update the codebook with a new observation.
     * @param x a new observation.
     */
    void update(double[] x);

    /**
     * Quantize a new observation. Returns Optional.empty
     * if the observation is noise.
     * @param x a new observation.
     * @return the quantized vector.
     */
    double[] quantize(double[] x);
}
